The structure and modified properties of a self-dimerised Cu(II) inclusion complex in γ-cyclodextrins.

Inclusion structures incorporating more than one guest molecule are elusive because confinement alters their molecular properties. We report the solid-state characterization of an inclusion complex comprising two γ-cyclodextrins and two [Cu(2-pyridinemethanolate)(2-pyridinemethanol)]PF6 units. Quantum calculation reveals that interfragment charge transfer occurs. The confined Cu fragment and the unincluded "linear chain [Cu(2-pyridinemethanolate)(2-pyridinemethanol)]PF6" exhibit different properties.

Crystal structure of bis-(1,10-phenanthroline-κ2N,N')(1,3-thia-zole-2-thiol-ato-κ2S2,N)nickel(II) hexa-fluorido-phosphate 1,4-dioxane sesquisolvate.

The title salt, [Ni(C3H2NS2)(C12H8N2)2]PF6·1.5C4H8O2, was the unexpected product on making an attempt to prepare an [Ni(2-mercapto-thia-zol-ate)(1,10-phenanthroline)]+ complex by reaction of [NiCl2(1,10-phen-an-throline)] with 2-mercapto-thia-zolate. In the resulting complex, the 2-mercapto-thia-zolate anion acts as a chelating ligand, which coordinates to the NiII ion with the thia-zolyl N and thiol-ate S atoms. In the crystal, π-π stacking inter-actions between the coordinating 1,10-phenanthroline mol-ecules of adjacent complexes result in a zigzag chain running parallel to the c axis. Weak C-H⋯X (X = O, F) hydrogen-bonding inter-actions between the chains and 1,4-dioxane solvent mol-ecules and PF6- counter-anions lead to the formation of sheets parallel to the ac plane.

pH-Dependent structural diversity of a 2-pyridinemethanol Cu complex and its relatively strong magnetic exchange coupling via hydrogen bonding.

The diversity of the self-assembled structures of a Cu complex via hydrogen bonding, including a square planar unit, is reported. The Cu complex forms two self-assembled structures by hydrogen bonding, depending on the acidity of the recrystallization conditions. A linear chain structure can be produced under acidic conditions, and a three-dimensional network structure is observed under basic conditions. The linear chain structure is constructed from intermolecular sharing of a hydrogen atom between two 2-pyridinemethanolate units, with an OO distance of 2.412(1) Å and an O-H-O bond angle of 170(3)°. The linear chain structure exhibits relatively strong magnetic coupling (J = -9.91(2) cm-1) via hydrogen bonding between Cu atoms; this coupling was also confirmed by electron spin resonance experiments. Thermochromic behavior was also observed for the complex.

Structural transformations of layered structures constructed from Cu(ii)-chloranilate monomer compounds.

Hydrogen-bond supported intercalation compounds constructed from three types of two-dimensional layers and common guests, {(Hha)2[Cu(CA)2(EtOH)2]}n (1), {(Hha)2[Cu(CA)2(EtOH)]}n (2), and {(Hha)2[Cu(CA)2]}n (3) (ha = hexylamine), have been synthesized and characterized. The hexylaminium cations are introduced between the anionic layers of the metal-chloranilate by not only electrostatic interactions but also hydrogen bonding interactions. These compounds show reversible EtOH adsorption and desorption accompanied by a structural transformation. With a change in the interaction between the mononuclear complexes of the host layer, the interaction between the host layer and the intercalated guest cations also changes. Moreover, the mobility and flexibility of the intercalated Hha+ cations enable the rearrangement of the mononuclear complexes while maintaining their layer structure. Thus, these compounds have flexibilities both in the inter- and intra-layers.

Competing ferro- and antiferromagnetic interactions in a hexagonal bipyramidal nickel thiolate cluster.

A new hexagonal bipyramidal Ni8 cluster is reported and its magnetic behaviour is analyzed. The molecular structure consists of a hexagonal wheel capped by two additional apical Ni(2+) ions. This structure supports ferromagnetic superexchange interactions between adjacent Ni(2+) ions in the wheel and an antiferromagnetic superexchange interaction between the wheel and apical Ni(2+) ions.

Bis[(5-bromo-pyridin-2-yl)methano-lato-κ(2) N,O]copper(II) monohydrate.

In the title compound, [Cu(C6H5BrNO)2]·H2O, the Cu(II) ion has a square-planer N2O2 coordination environment. Slipped π-π stackings [centroid-centroid distances: 3.625 (3), 3.767 (3), 3.935 (3) and 4.255 (3) Å] between pyridine rings and Cu⋯π inter-actions (centroid-to-Cu(II) distance: 3.56 Å) between Cu(2+) ions and pyridine rings lead to a layered arrangement parallel to (010). Inter-molecular Br⋯O inter-actions [Br⋯O distances: 2.904 (3) and 3.042 (3) Å] and O-H⋯O hydrogen bonds form a three-dimensional network structure.

Bis(2,2'-bipyridine)(pyridin-2-olato)ruthenium(II) hexa-fluorido-phosphate benzene hemisolvate.

In the title compound, [Ru(C(5)H(4)NO)(C(10)H(8)N(2))(2)]PF(6)·0.5C(6)H(6), the Ru(2+) cation has a distorted octa-hedral RuN(5)O coordination environment. This complex is more distorted than the closely related ruthenium complex containing a pyridine-2-thiol-ate ligand [Santra et al. (1997 ▶). J. Chem. Soc. Dalton Trans. pp. 1387-1393]. The distortion is caused by the difference in size between the O and S atoms. The benzene solvent mol-ecule is situated on a twofold rotation axis.

Tris(pyridin-2-yl-methanol)nickel(II) hexa-fluoridophosphate trifluoro-acetate.

In the crystal structure of the title complex, [Ni(C(6)H(7)NO)(3)](PF(6))(C(2)F(3)O(2)), the Ni(II) ion is in a slightly distorted octa-hedral NiO(3)N(3) coordination geometry with each of the three N and three O atoms in a meridional coordination. In the crystal, the complex mol-ecules and the trifluoro-acetate anions are connected via O-H⋯O hydrogen bonding into layers parallel to the ab plane.

Novel 2-mercaptopyridine-ruthenium complex exhibiting electrochemically induced linkage isomerization switched on/off by protolysis.

A ruthenium complex [ruthenium bis(2,2'-bipyridine)(2-mercaptopyridine)(pyridine)](PF6)2 was crystallographically characterized from its deprotonated form and was electrochemically investigated. In the deprotonated complex, the 2-mercaptopyridine ligand coordinates to the Ru atom only by the S atom; therefore, the N atom of the 2-mercaptopyridine ligand can be protonated. In a CH3CN solution, the complex shows a reversible redox couple attributed to RuIII/II-S. The addition of a base to the CH3CN solution of the complex gives irreversible voltammograms, implying electrochemically induced linkage isomerization between RuII-S and RuIII-N. Analysis of the observed cyclic voltammograms gave the equilibrium and rate constants for linkage isomerization: KIINS = 1.2 x 1018, KIIINS = 0.64, kIINS = 5 x 10 s(-1), kIISN = 4 x 10-17 s(-1), kIIINS = 0.26 s(-1), and kIIISN = 0.40 s(-1).